President Barack Obama declared a “new day” in U.S.-Cuban relations, but acknowledged “serious differences” exist between the two countries in remarks at a news conference with Cuban President Raúl Castro in Havana. Mr. Obama met with Mr. Castro at the Palace of the Revolution at the start of a full day of official events marking his historic state visit. Mr. Obama’s trip comes as the U.S. is readying an announcement that Google will begin wiring the island for Internet access. Mr. Obama said that expanding Internet access for Cubans is key to changing the country.

Obama Welcomed by Raul Castro

A Donald Trump presidential nomination would usher in a new philosophical era for the Republican Party, with longstanding commitments to such positions as free trade at odds with the businessman’s populist message, writes WSJ’s Gerald F. Seib. Meantime, without mentioning Mr. Trump by name, Hillary Clinton told a leading pro-Israel lobby that the Republican front-runner’s foreign policy proposals could undercut American leadership on the world stage and jeopardize the Jewish state’s security.

Looking Ahead to Tuesday Primaries

Fantasy-sports operators FanDuel and DraftKings agreed to shut down in New York, their largest market, as part of a settlement with the state attorney general’s office. The fight in New York comes as more than two dozen states weigh legislation on daily fantasy sports. The New York attorney general has said daily fantasy sports constitute gambling because players are “placing bets on events outside of their control or influence,” but the operators have said daily fantasy sports is a game of skill and not akin to gambling.

Researchers are unlocking some of the mysteries surrounding migraines, raising hopes for a new class of treatments. Drugs taken to treat debilitating headaches don’t work in all patients. Meanwhile, drugs taken to prevent attacks were developed to fight other conditions, like high blood pressure, and have limited effectiveness. Today several companies are in the late stages of testing a new class of migraine drug that target a chemical known as CGRP, that researchers have found is involved in the brain’s pain-signaling during migraines.